1. Field of the Invention
This invention relates to a catalyst for the production of ethylene oxide and a method for the production of ethylene oxide. In more detail, this invention relates to a catalyst for the production of ethylene oxide superior in selectivity of ethylene oxide and catalyst life, and is capable of producing ethylene oxide in high selectivity for a long period of time, and a method for the production of ethylene oxide using this catalyst for the production of ethylene oxide.
2. Description of the Related Art
It has been widely performed industrially to produce ethylene oxide by catalytic vapor phase oxidation of ethylene with a molecular oxygen-containing gas in the presence of a silver catalyst. As for the silver catalyst to be used in this catalytic vapor phase oxidation, various technologies have been proposed on a carrier thereof, a supporting method, and a reaction promoter or the like.
Catalytic activity, selectivity and catalyst life of the silver catalyst have reached a high level already, however, still more enhancement of catalytic performance thereof has been required. For example, as for selectivity, because of a large production scale of ethylene oxide, even only 1% of enhancement of selectivity provides extreme saving of use amount of ethylene as law material, and economical effect thereof is large. Under such circumstance, development of the silver catalyst having more superior catalytic performance and pursuit of high efficiency or enhancement of selectivity of catalytic vapor phase oxidation reaction in a multi-tube type reactor using the same have been continuous themes of researchers in the relevant technical field.
For example, WO 2004/101144 discloses a catalyst having silver supported on a carrier having α-alumina as a main component, and describes about suitable catalyst size, amount of silver supported, as well as amount of silver loaded in a catalyst layer obtained by packing the catalyst in a reactor. In addition, for example, JP-A-2002-306953 describes that a catalyst can be packed uniformly and used stably for a long period of time by packing the catalyst in a reaction tube of a fixed-bed multi-tube type reactor at a prescribed rate. Further, for example, JP-A-2010-36115 discloses a method for packing a catalyst having a prescribed outer diameter or length into a reaction tube having a prescribed inner diameter, and describes about amount of silver contained in the catalyst layer.